Vulnerability identifier: #VU54028

Vulnerability risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2016-4956

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ntp
Server applications / Other server solutions

Vendor: ntp.org

Description

The vulnerability allows remote attackers to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input. A remote attacker can cause a denial of service (interleaved-mode transition and time change) via a spoofed broadcast packet.

Mitigation
Install update from vendor's website.

Vulnerable software versions

ntp: 4.0.72 - 4.2.8p7

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External links
http://support.ntp.org/bin/view/Main/NtpBug3042
http://www.kb.cert.org/vuls/id/321640
http://bugs.ntp.org/3042
http://support.ntp.org/bin/view/Main/SecurityNotice
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00023.html
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.html
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00024.html
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00028.html
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00040.html
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
http://www.securityfocus.com/bid/91009
http://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03757en_us
http://security.gentoo.org/glsa/201607-15
http://www.securitytracker.com/id/1036037
http://security.FreeBSD.org/advisories/FreeBSD-SA-16:24.ntp.asc
http://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.